Boosting N,N-Dimethylformamide Electrosynthesis via a Surface Active Additive

Electrosynthesis of N,N-dimethylformamide (DMF) via C─N coupling offers a sustainable alternative to energy-intensive thermal routes but is hindered by low reactant concentration at the anode and sluggish proton-coupled electron transfer. Here we report a new electrochemical route for DMF synthesis by the co-oxidation of dimethylamine and ethylene glycol. Notably, over a CuO electrode, the addition of 0.5 mM sodium dodecylbenzenesulfonate (SDBS) to the electrolyte significantly enhances reaction kinetics and Faradaic efficiency for DMF (FE_DMF), achieving a DMF production rate to 0.78 mmol h^-1 cm^-2, over three times higher than that without SDBS. Using a 25 cm² CuO electrode in 0.5 M NaHCO₃ with 0.5 mM SDBS, a current of approximately 2.0 A and a DMF production rate of 7.5 mmol h^-1 are achieved. Mechanistic investigations reveal that SDBS acts as a multifunctional ionic anchor, reorienting its sulfonate group toward the anode and projecting its hydrophobic tail into the electrolyte under reaction conditions. This configuration suppresses the oxygen evolution reaction while simultaneously enriching reactants, promoting deprotonation and proton transfer, and facilitating electron transfer, thereby enhancing both reaction kinetics and FE_DMF.